Closure bag for shot-holes



Oct. 8, 1963 E, D. ABRAMsoN 3,106,159

cLosuRE BAG Foa SHOT-HOLES Filed my 2s, 1962 2 sheets-snee: 1

INVENTOR ELMER D. ABRAMSON www ATTORNEY United States Patent Olice 3,106,159 Patented Oct. 8, 1963 3,196,159 CLOSURE BAG FOR SHOT-HLES Elmer D. Abramson, Creve Coeur, Mo., assigner to Centra] States Paper & Bag Co., St. Louis, Mo., a corporation of Missouri Filed July 23, 1962, Ser. No. 211,598 Claims. (Cl. 102-30) This invention relates in general to mining devices and, more particularly, to bags for closing the open ends of shot-holes.

In the mining of coal and other economically valuable ores, it is common practice to drill a series of holes into a face or wall of rock and place a charge of explosive therein. At a suitable distance from a line of explosivecharged holes or so-called shot-holes, the section of rock is undercut so that when the explosive is detonated, a quantity of ore will be blown down and can be removed. No matter how carefully the explosive is placed and tamped, a substantial quantity of dust, rock chips, and debris will be blown into the atmosphere during the course of the actual explosion, with the result that the workmen must wait between shots to allow the dust to settle in the immediate area before proceeding with other work. Moreover, the air in the entire mine is contaminated with rock-dust, thereby exposing the miners to the hazard of silicosis. Of course, numerous efforts have been made to combat the dust hazard in mines by tamping shot-holes with various materials, `but such procedures have proven to be costly. time-consuming, and have not been particularly successful.

It is, therefore, the primary object of the present invention to provide means and methods for closing the outer ends of shot-holes to prevent the blowing of dust and other similar debris into the atmosphere during the detonation of the explosive charges which have `been placed in the shot-holes.

It is another object of the present invention to provide a closure-device of the type and for the purpose stated which can be quickly and easily installed in a shot-hole and when so installed will effectively seal the shot-hole during the detonation of the charge which has been placed therein, so as to prevent dust, dirt, rock chips, and similar debris from being blown into the atmosphere of the mine, and `ultimately circulated throughout the entire air system thereof.

It is a further object of the present invention to provide an elongated self-closing resilient bag which can be quickly and easily placed in a shot-hole and inated with a suitable uid, such as water for instance, and thereby securely close or seal the shot-hole.

It is an additional object of the present invention to provide shot-hole closure bags of the type stated which are made of a synthetic resin sheeting and are, therefore, relatively inexpensive.

It is likewise an object of `the present invention to provide a simple, economical, and highly efcient method of manufacturing shot-hole closure bags of the type stated.

With the 'above and other objects in view, my invention resides in the novel features of form, construction, arrangement, and combination of parts presently described and pointed out in the claims.

In the accompanying drawings (two sheets)- FIG. `l is a top plan view of a shot-hole closure bag constructed in accordance with and embodying the present invention;

FIGS. 2 and 3 `are sectional views taken along lines 2-2 and 3-3, respectively, of FIG. l;

FIG. 4 is a longitudinal sectional view of the shot-hole cl-osure bag in inflated or closure-forming condition;

FIG. 5 is a transverse sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is a fragmentary perspective view of a section of rock wall illustrating the method of sealing a shot-hole using the closure-bag of the present invention;

FIG. 7 is a schematic perspective view illustrating an initial stage in the process of manufacturing closure bags according to the present invention;

FIG. 8 is a plan view of the valve-forming assembly forming a part of the present invention;

FIG. 9 is a schematic perspective view illustrating an intermediate stage in the method of manufacturing closure bags according `to the present invention;

FIG. 10 is a fragmentary front elevational view of a typical heat-sealing press used in connection with the process off the present invention;

FIG. l1 is a fragmentary sectional view `taken along line 11--11 of FIG. 8;

FIG. 12 is a top plan View of a finished section or panel of closure bags constructed in accordance with and embodying the present invention; and

FIGS. 13 and 14 are fragmentary sectional views taken along lines 13-13 and 14-14, respectively, of FIG. `l2.

Referring now in more detail and by reference characters to the drawings, which illustrate a preferred embodiment of the present invention, A designates a single closure bag which comprises an elongated tubular element 1 which is somewhat tapered at its bottom for permanentlyclosed end 2. At its other or initially-open end 3, `the closure bag A is internally provided with a self-closing valve 4 which projects axially outwardly `and opens exteriorly so as to permit an appropriate fluid, such as water, to be charged under pressure into the bag A, thereby inllating it as shown in FIG. 4.

Preferably, the closure bag A consists of two flat `facewise overlying plies or walls S, 6, formed of a suitable thermoplastic sheeting made of a synthetic resin, which is capable of being heat-sealed either by the heated dies or in a high frequency press. Thermoplastic films or sheeting made of synthetic resins such as polyvinyl chloride, acrylonitrile butadiene styrene, `acrylonitn'le styrene copolymers, cellulose acetate, cellulose triacetate, cellulose acetate butyrate, ethyl cellulose, polyamide, polycarbonate, polyester, polyester copolymers, polytrifluorochloro ethylene, polymethyl methacrylate, polyethylene, polypropylene, polytetrauoro ethylene, fluorinated ethylene, polystyrene, vinyl chloride/acetate copolymers, vinylidene chloride/vinyl chloride copolymers, polyvinyl fluoride, rubber hydrochloride, and vinyl nitrile rubber, have been found to be satisfactory for purposes of this invention. The plies or walls 5, 6, are secured together by a con-tinuous somewhat elongated U-shaped marginal heat-seam 7 which terminates at the outer laterally spaced comers of the initially-open end 3. The self-closing valve 4 similarly consists of two facewise overlying plies or flaps 8, 9, formed of the same thermoplastic material and marginally incorporated within the heat-seam 7 adjacent the initiallyopen end 3. The aps 8, 9, are separately secured to the plies 5, 6, across the open end or so-called mouth of the bag A by means of transverse heat-seams 10, 11, respectively, and, in addition thereto, are mutually secured to each other by inwardly extending somewhat covering heatseams 12, 13, so as to provide an inwardly tapering inlet passage 14.

The closure bag A may be of any dimensions depending upon the diametral size and depth of the shot-hole into which the closure bag A is to be placed. It has been found preferable, however, to make the closure bag A at least ten to twelve inches long so that it will extend into the shot-hole `for a sufficient distance to provide a secure and highly effective plugging of the shot-hole. Moreover, the closure bag A must have a diametral size substantially equal to, or slightly smaller than, the diametral size of the shot-hole. Thus, the closure bag A may be initially lled with water or other similar iiuid until it is fully extended and rigidized. In this condition, it can be readily handled and easily inserted into the shot-hole to the full extent of its length, leaving a very small portion projecting outwardly for convenience in manual gripping. Thereupon, a water hose or other source of fluid under pressure can be inserted through the mouth m and into the valve 4 so that an additional amount of water can be injected into the interior of the closure bag A, thereby distending or inating it tightly and conformably to the wall-surfaces of the shot-hole. Of course, it should be understood that the amount of duid-pressure which is injected into the closure bag A should not be unduly excessive to the extreme of rupturing the relatively thin exible walls 5, 6, but, it has been found in this connection that by using synthetic-resin sheeting of commercially available thicknesses, the closure bag A is capable of withstanding pressures which are more than adequate to force the surfaces of the closure bag A into tight sealing engagement Within the shothole, substantially as shown in FIG. 6. In connection with FIG. 6, it should be noted incidentally, that no effort has been made to illustrate the presence of an explosive charge within the shot-hole S, but it will be apparent to one skilled in this art that an explosive charge is set into the shot-hole S in the usual manner prior to installation of the closure bag A.

The valve 4, being fabricated of two overlying ilexible plies of material, will immediately close as soon as the huid-injecting nozzle (not shown) is withdrawn. Therefore, when the closure bag A is charged with fluid under pressure and is in tightly distended position, iluid pressure will be retained within the closure bag A and the valve 4 will assume a closed position, substantially as shown in FIGS. 4 and 5. If, for any reason, it should become desirable and necessary to deflate the closure bag, it is merely necessary to insert a small blunt-ended rod-like instrument through the mouth end and `displace the flaps 8, 9, from `racewise overlying engagement with each other. Immediately iuid will ow outwardly through the passage 14 thereby permitting the walls 5, 6, to collapse to the degree desired. When the explosive within the shot-hole is detonated, the closure bag A will ordinarily resist rupturing and will remain intact, at least for `a substantial number of seconds after the explosion 'and until the rock or ore has begun to drop. In fact, it has been found that the closure bag A usually does not rupture at all, except upon being physically punctured bythe falling rock or ore. However, if the closure bags A are punctured or ruptured during the early instants of the explosion, this is a desirable, rather than undesirable, result because the water contained within the closure bag A will thereupon be sprayed into the immediate region of the shot-hole S :and dampen any dust generated by the explosion. As a matter of actual experience, it has been found that, thro-ugh the use of closure bags A, it is possible to carry out virtually dust-free shooting in mining operations.

Although it is undoubtedly possible to manufacture the closure bags A by various different methods, it has been found preferable to employ the process of manufacture schematically shown in FIGS. 7-11, inclusive. According to this procedure two oblong-rectangular sections of polyvinyl chloride sheeting 15, 16, are superposed in marginal registration with an elongated ribbon-like piece of cellophane or other non-thermoplastic film 17 interposed between and projecting outwardly from the overlying longitudinal margins 18, 19, of the sections 1S, 16, las best seen `in FIG. 8. This stack [assembly is placed in a suitable heated press, such as that shown diagrammatically in FIG. 10, and a series of laterally spaced heat-seams 20, 21, 22, 23, 24, and 25, are impressed therein. The inner four heatsearns 21, 22, 23, 24, are of inverted U-shape with downwardly diverging side legs and the outermost heat-seams 20, and 25, are, in effect, opposite halves of a single one of the intermediate heatseams 21, 22, 23, 24. Thus, the sheets 15, 16, are welded together to form ve side-by-side valve elements 4. It will, of course, be understood in this connection, that it would be possible to make the sheets 15, 16, much longer and, by using larger heat-sealing equipment, form a greater number of such valve elements 4, the limit being a matter of handling convenience and etiiciency.

The valve element assembly, as shown in FIG. 8, is then placed between two relatively large oblong-rectangular sections of polyvinyl chloride sheeting 26, 27, and stacked in the manner shown in FIG. 9. In this connection, it should be noted that the one section 26 is somewhat shorter in length than the other section 27 and the bottom margins 28, 29, as well as the side margins 30, 31, and 32, 33, respectively thereof, are in overlying registration. However, the upper margins 34, 35, are not in overlying registration, but instead, are arranged in step-wise succession, las shown in FIG. 14. Thus, t-he margin 34 is innermost, the margin 35 is outermost, and the registering margins 18, 19, of the sections 15, 16, are located in an intermediate position. Finally, the outer longitudinal margin of the strip 17, preferably, projects out beyond the margin 34.

The stacked assembly consisting of the sections 26, 27, and the previously heat-seam valve element strip are `placed in `a suitable heat-sealing press, substantially as shown in FIG. 10, and the transverse heat-seams 10, 11, as well as the marginal heat-seam 7 are impressed therein as shown in FIGS. l2 and 13.

The heat-seam 10 securely welds `the section 26 to the section 15 and, similarly, the heat-seam 11 welds the section 27 to the section 16, but, by reason of the interposition of the non-thermoplastic strip 17, the two heatseams 10, 11, are kept separate and the inner or contiguous faces of the sections 15, 16, remain separable. Similarly, the upper parallel portions of the heat-seam 7 weld the sections 26, 15, 16, and 27, to each other. Moreover, the heat-seams 7 almost, but not quite, penetrate through the overlying plies of material and, therefore, fall just shont of citt-seeming, so las to leave a thin readily rupturable `integuiment between each of the live closure bags A which constitute the completed section or panel of closure bags shown in FIG. ll.

In use, the workman merely removes the strip 17 from a connected section or panel of closure bag and discards it. Thereupon, the closure bags A are torn, one at a time, from the section or panel so that it is thereby separated into tive individual closure bags A. As noted above, it has been found convenient and practical to embody five such closure bags A in a single panel, but a different number may be employed if, `for `any reason, it is desirable to do so. The separate or individual closure bags A are each filled with fluid in the manner above described and installed in shot-holes, substantially as shown in FIG. 6.

It should be understood that changes and modifications in the form, construction, arrangement, and combination of the several pants of the mining devices may be made and substituted for those herein shown and described without departing from the nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. A bag for closing shot-holes in mining operations, said bag comprising an elongated tubular member of generally rectilinear peripheral original shape and being relatively long in its lengthwise dimension and relatively `narrow in its transverse dimension, said bag being formed of a flexible thermoplastic material, said tubular member being entirely cio-sed across one narrow end and provided at the other end with a mouth through which .a non-compressible lling medium may be charged into the bag, said mouth extending substantially entirely across the other transverse end, and valve means operatively disposed across said mouth for retaining the filling medium within the bag whenever it is charged thereinto, said valve means consisting of two normally dat facewise overlying plies of flexible thermoplastic material joined together along their longitudinal margins in the formation of a short tube having substantially the same transverse width as the tubular member but being substantially shorter than said tubular member, said plies being sealed along said longitudinal margins to the longitudinal margins of the tubular member in the form of common side-seams, said plies also being provided interiorly of their longitudinal margins with spaced intermediate seams dening a longitudinal passageway establishing communication between said mouth and the interior of the tubular member, the portions of the plies between the respective side-seams and the proximate intermediate seam forming retention webs whereby the passageway is held in operative position.

2. A bag for closing shot-holes `in mining operations, said bag comprising an elongated tubular member of generally rectilinear peripheral original shape and being relatively long in its lengthwise dimension and relatively narrow in its transverse dimension, said bag being formed of a flexible thermoplastic material of the class consisting of polyvinyl chloride, acrylonitrile butadiene styrene, acrylonitrile styrene copolymers, cellulose acetate, cellulose triacetate, cellulose acetate butyrate, ethyl cellulose, polyamide, polycarbonate, polyester, polyester copolymers, polytriuorochloro ethylene, polymethyl methacrylate, polyethylene, polypropylene, polytetrauoro ethylene, uorinated ethylene, polystyrene, vinyl chloride/ acetate copolymers, vinylidene chloride/vinyl chloride copolymers, polyvinyl tluoride, rubber hydrochloride, and vinyl nitrile rubber, said tubular member being entirely closed across one narrow end and provided at the other end with a mouth through which a non-compressible filling medium may be charged into the bag, said mouth extending substantially entirely across the other transverse end, and valve means operatively disposed across said mouth for retaining the filling medium within the bag whenever it is charged thereinto, said valve means consisting of two normally at facewise overlying plies of ilexible thermoplastic material joined together along their longitudinal margins in the formation of a short tube having substantially the same transverse width as the tubular member but being substantially shorter than said tubular member, said plies being sealed along said longitudinal margins to the longitudinal margins of the tubular member in the form of common side-seams, said plies also being provided interiorly of their longitudinal margins with spaced intermediate seams `dening a longitudinal passageway establishing communication between said mouth and the interior of the tubular member, the portions of the plies between the respective side-seams and the proximate intermediate seam thereby forming retention webs whereby the passageway is held in operative position.

3. A bag according to claim 1 in which the intermediate seams converge arcuately toward each other from the outer corners of the mouth, and the plies forming the valve means are seamed respectively to the opposite walls of the tubular member inwardly of their transverse margins.

4. A bag according to claim 1 in which the mouth forming portions of the tubular member and the plies of the valve means are respectively sealed together but are `disjunctive along the outer portions of the side-seams so as to form two separate aps on opposite sides of the mouth across the entire mouth end of the bag.

5. A bag `for closing shot-holes in mining operations, according to claim 4 and having a non-thermoplastic material removably disposed across said mouth, between said flaps.

References Cited in the le of this patent UNITED STATES PATENTS 2,449,645 Du Pont et al Sept. 21, `1948 2,697,531 Hood Dec. 2l, 1954 2,799,314 Dreyer et al. July 16, 1957 2,804,257 Hasler et al Aug. 27, 1957 2,856,002 True et al. Oct. 14, 1958 2,916,995 Douglass et al Dec. 15, 1959 3,006,257 Orsini Oct. 31, 1961 3,069,978 Hoeppner Dec. 25, 1962 FOREIGN PATENTS 1,039,203 France May 13, 1953 

1. A BAG FOR CLOSING SHOT-HOLES IN MINING OPERATIONS, SAID BAG COMPRISING AN ELONGATED TUBULAR MEMBER OF GENERALLY RECTIAINEAR PERIPHERAL ORIGINAL SHAPE AND BEING RELATIVELY LONG IN ITS LENGTHWISE DIMENSION AND RELATIVELY NARROW IN ITS TRANSCERSE DIMENSION, SAID BAG BEING FORMED OF A FLEXIBLE THERMOPLASTIC MATERIAL, SAID TUBULAR MEMBER BEING ENTIRELY CLOSED ACROSS ONE NARROW END AND PROVIDED AT THE OTHER END WITH A MOUTH THROUGH WHICH A NON-COMPRESSIBLE FILLING MEDIUM MAY BE CHARGED INTO THE BAG, SAID MOUTH EXTENDING SUBSTANTIALLY ENTIRELY ACROSS THE OTHER TRANSVERSE END, AND VALVE MEANS OPERATIVELY DISPOSED ACROSS SAID MOUTH FOR RETAINING THE FILLING MEDIUM WITHIN THE BAG WHENEVER IT IS CHARGED THEREINTO, SAID VALVE MEANS CONSISTING OF TWO NORMALLY FLAT FACEWISE OVERLYING PLIES OF FLEXIBLE THEREMOPLASTIC MATERIAL JOINED TOGETHER ALONG THEIR LONGITUDINAL MARGINS IN THE FORMATION OF A SHORT TUBE HAVING SUSSTANTIALLY THE SAME TRANSVERSE WIDTH AS THE TUBULAR MEMBER BUT BEING SUBSTANTIALLY SHORTER THAN SAID TUBULAR MEMBER, SAID PLIES BEING SEALED ALONG SAID LONGITUDINAL MARGINS TO THE LONGITUDINAL MARGINS OF THE TUBULAR MEMBER IN THE FORM OF COMMON SIDE-SEMAS, SAID PLIES ALSO BEING PROVIDED INTERIORLY OF THEIR LONGITUDINAL MARGINS WITH SPACED INTERMEDIATE SEAMS DEFINING A LONGITUDINAL PASSAGEWAY ESTABLISHING COMMUNICATION BETWEEN SAID MOUTH AND THE INTERIOR OF THE TUBULAR MEMBER, THE PORTIONS OF THE PLIES BETWEEN THE RESPECTIVE SIDE-SEAMS AND THE PROXIMATE INTERMEDIATE SEAM FORMING RETENTION WEBS WHEREBY THE PASSAGEWAY IS HELD IN OPERATIVE POSITION. 